Rail vehicle signal enforcement and separation control

ABSTRACT

A system for vehicle management includes a control signal interface subsystem and a vehicle-mounted subsystem. Each of these subsystems includes an ultra-wideband (UWB) communications component. The subsystems communicate with each other through the UWB components. The vehicle mounted subsystem interfaces with a braking system of the vehicle. The vehicle mounted subsystem determines the distance between it and the control signal interface subsystem based on the time-of-flight of at least one communication between the subsystems. The vehicle-mounted subsystem can cause the braking system of the vehicle to activate if the distance between the vehicle-mounted subsystem and the control signal interface subsystem is less than a threshold.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/476,338, filed Sep. 3, 2014, and claims priority to U.S. ProvisionalPatent Application No. 61/959,729, entitled “Light Rail Control System,”filed on Sep. 3, 2013, each of which is incorporated by reference in itsentirety herein.

FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[Not Applicable]

JOINT RESEARCH AGREEMENT

[Not Applicable]

SEQUENCE LISTING

[Not Applicable]

BACKGROUND

Railroads have had several severe collisions and other accidents, someresulting in fatalities, when adequate spacing has not been maintainedbetween rail vehicles. A major issue causing rail collisions involvesvehicle operators failing to respond to a control point signal, such asa stop signal. For example, vehicle operators may fail to notice acontrol point signal due to visibility issues, equipment errors,operator maladies, or negligence. In such a situation, rail vehicles maycontinue to travel along a track not safe for travel, potentiallyresulting in disastrous collisions and/or accidents.

The Federal Railroad Administration established a system of railregulations called positive train control (“PTC”). PTC is a system offunctional regulations for monitoring and controlling train movements toprovide increased safety. PTC, however, is an expensive system that isdifficult to implement, particularly in light of the technologypresently available. For public transit systems, PTC will generallyincrease travel time, passenger wait time, and decreased throughput.

Moreover, problems can also occur on railroads when sufficient spacingbetween rail vehicles is not properly maintained. Rail vehicle spacingcan be monitored and maintained using various equipment and sensorsinstalled on rail vehicles. For example, spacing between vehicles may bemonitored by use of a global positioning system (“GPS”) that tracks andfollows the location of rail vehicles on a rail track.

However, present methods and systems for controlling and enforcing railvehicle separation can be insufficient, particularly under certaincircumstances. For example, in subterranean tunnels, or subways, railvehicles may not have a clear view of the sky, and therefore, may not betraceable by GPS methods. It can therefore be difficult for the operatorof such a rail vehicle, to know the location, speed, and position of therail vehicle relative to other vehicles on the train track with theaccuracy necessary to operate safely and efficiently. Moreover, it canbe difficult for a rail vehicle control system to properly enforceseparation among rail vehicles on a railroad track if the preciselocation of each rail vehicle is not accurately known. For example, PTCcan “dead-reckon” using the odometer in non-GPS areas, but there may bedegradation in accuracy. This degradation may be acute in commuter railapplications where train spacing is less than with freight rail.

SUMMARY

Certain embodiments of the present technology provide a rail vehiclecontrol system installable on a rail vehicle. The rail vehicle controlsystem can include a collision avoidance system including a transpondersensor module. In some embodiments, the transponder sensor module isoperable to communicate with one or more transponder sensor modulesinstalled on one or more proximate rail vehicles, and/or one or moresignal control points to detect a distance between the rail vehicle andthe proximate vehicle and/or the signal control point. For example, incertain aspects of the present technology, the collision avoidancesystem can detect a distance between the rail vehicle and the proximaterail vehicle or signal control point based at least in part on the timeit takes a signal to travel between the transponder sensor modules. Thecontrol system can also include a radio frequency identification(“RFID”) reader adapted to detect serialized RFID tags mounted atlocations along a railroad. In certain aspects, the vehicle separationcontrol system includes a data collection system operable to obtain railvehicle information from the collision avoidance system and the RFIDreader. The data collection system can include, for example, a datastorage device. In some embodiments, the rail vehicle control systemincludes a supervisory component in communication with the collisionavoidance system, the RFID reader, and the data collection system. Thesupervisory component can be operable, for example, to communicate railvehicle information to a rail network.

Certain embodiments of the present technology provide a railroad controlsystem operable to manage rail vehicle separation on a railroad track.The railroad control system can include a rail network that maintainsinformation relating to the location and speed of rail vehicles on therailroad track. In some embodiments, the railroad control systemincludes multiple serialized RFID tags mounted at locations along therailroad track. The railroad control system can also include at leastone signal control point located along the railroad track. Each signalcontrol point can be operable to display signals viewable by a railvehicle operator. In some embodiments, the signal control pointscomprise a station transponder sensor module operable to send andreceive wireless signals. Each signal control point can also be operableto communicate with the rail network. Some embodiments also include avehicle mounted system installable on a rail vehicle. The vehiclemounted system can include a vehicle transponder sensor module operableto communicate with a station transponder sensor modules installed in asignal control point to detect a distance between the rail vehicle andthe signal control point. The vehicle mounted system can also include aRFID reader adapted to detect the serialized RFID tags mounted along therailroad track. In certain embodiments, the vehicle mounted system alsoincludes data collection system in communication with the vehicletransponder sensor module and the RFID reader. The data collectionsystem can also include a data storage device. In some aspects, thevehicle mounted system also includes a supervisory component operable tocommunicate with the rail network. In some embodiments of the presenttechnology, the vehicle mounted system obtains vehicle informationrelating to the railroad track that the rail vehicle is traveling upon,the rail vehicle location, and the rail vehicle speed based on theserialized RFID tags detected by the RFID reader. In some embodiments,the vehicle mounted system can also communicate the vehicle informationto the rail network.

The present disclosure also provides a method for determining the speedand location of a rail vehicle traveling on a railroad track. The methodcan include the step of detecting a first serialized RFID tag installedalong a railroad track with an RFID reader installed on the railvehicle, where the first serialized RFID tag is detected at a first time(e.g., time t1). The method can also include the step of detecting asecond serialized RFID tag installed along the railroad track with theRFID reader, where the second serialized RFID tag is detected at asecond time (e.g., an earlier or later time t2). The method can alsoinclude the step of referencing a database to obtain informationrelating to the location of the first and second serialized RFID tags.In some embodiments, the method includes determining vehicle locationinformation based at least in part on the information relating to thelocation of the first and second serialized RFID tags. Some embodimentsof the method can also include determining vehicle speed informationbased at least in part on the location of the first RFID tag and thefirst time, and the location of the second RFID tag and the second time.The method can also include the step of communicating the vehiclelocation information and the vehicle speed information to a railnetwork, for example, communicating the information to a rail networkvia a reporting station installed along a railroad track.

Certain embodiments of the present technology also provide a method forenforcing rail vehicle adherence to control signals. The method cancomprise the step of communicating a control signal via a signal controlpoint. In some aspects, the method includes the step of detecting adistance between a rail vehicle and the signal control point using acollision avoidance system. In some embodiments, the step of determininga distance can be based at least in part on the time it takes a signalto travel between the transponder sensor modules on the rail vehicle andsignal control point, for example. The collision avoidance system cancomprise, for example, one or more transponder sensor modules installedon each of the rail vehicle and the signal control point. In certainembodiments, the method includes the step of generating a warning signalon the rail vehicle via a warning system when the collision avoidancesystem detects that the rail vehicle is approaching a signal controlpoint that is communicating a stop signal. In some embodiments, themethod can also include the step of automatically braking the railvehicle when the collision avoidance system detects that the railvehicle is not observing a stop signal communicated by the signalcontrol point.

Certain embodiments of the present technology provide for a system forvehicle management. The system includes a control signal interfacesubsystem including an ultra-wideband (UWB) communications component.The system also includes a vehicle-mounted subsystem including a UWBcommunications component. The vehicle-mounted subsystem is configuredto: interface with a braking system of the vehicle; communicate with theUWB communications component of the control signal interface subsystemvia the UWB communications component of the vehicle-mounted subsystem;and determine a distance between the vehicle-mounted subsystem and thecontrol signal interface subsystem based on a time-of-flight of at leastone communication between the UWB communications component of thecontrol signal interface subsystem and the UWB communications componentof the vehicle-mounted subsystem.

According to a technique, the vehicle-mounted subsystem is furtherconfigured to generate an alert if the distance between thevehicle-mounted subsystem and the control signal interface is less thana threshold. According to another technique, the vehicle-mountedsubsystem is further configured to cause the braking system of thevehicle to activate if the distance between the vehicle-mountedsubsystem and the control signal interface is less than a threshold.According to another technique, the vehicle-mounted subsystem furtherincludes: a radio-frequency identification (RFID) subsystem configuredto scan at least one RFID tag external to the vehicle to retrieveinformation stored on the at least one RFID tag. In this technique, thevehicle-mounted subsystem is further configured to determine a distancebetween the vehicle-mounted subsystem and the control signal interfacesubsystem based on the information stored on the at least one RFID tag.According to another technique, the vehicle-mounted subsystem is furtherconfigured to substantially continuously receive information relating tospeed of the vehicle. The vehicle-mounted subsystem determines achanging distance between the vehicle-mounted subsystem and the controlsignal interface subsystem based on the information stored on the atleast one RFID tag and the information relating to speed of the vehicle.According to another technique, the system further includes an accesspoint external to the vehicle. In this technique, the vehicle-mountedsubsystem is further configured to: store data relating to priorbehavior of the vehicle; and communicate the data relating to priorbehavior of the vehicle with the access point.

Certain embodiments of the present technology provide for a system forvehicle management that includes: a control signal interface subsystemincluding an ultra-wideband (UWB) communications component; a firstvehicle-mounted subsystem including a UWB communications component,wherein the first vehicle-mounted subsystem is configured to interfacewith a braking system of the vehicle; and a second vehicle-mountedsubsystem including a UWB communications component, wherein the secondvehicle-mounted subsystem is configured to be mounted on anothervehicle. The first vehicle-mounted subsystem is configured to:communicate with the UWB communications component of the control signalinterface subsystem via the UWB communications component of the firstvehicle-mounted subsystem; communicate with the UWB communicationscomponent of the second vehicle-mounted subsystem via the UWBcommunications component of the first vehicle-mounted subsystem;determine a distance between the first vehicle-mounted subsystem and thecontrol signal interface subsystem based on a time-of-flight of at leastone communication between the UWB communications component of thecontrol signal interface subsystem and the UWB communications componentof the first vehicle-mounted subsystem; and determine a distance betweenthe first vehicle-mounted subsystem and the second vehicle-mountedsubsystem based on a time-of-flight of at least one communicationbetween the UWB communications component of the second vehicle-mountedsubsystem and the UWB communications component of the firstvehicle-mounted subsystem.

According to one technique, the first vehicle-mounted subsystem isfurther configured to: generate an alert if the distance between thefirst vehicle-mounted subsystem and the control signal interface is lessthan a first threshold; and generate an alert if the distance betweenthe first vehicle-mounted subsystem and the second vehicle-mountedsubsystem is less than a second threshold. According to anothertechnique, the first vehicle-mounted subsystem is further configured to:cause the braking system of the vehicle to activate if the distancebetween the first vehicle-mounted subsystem and the control signalinterface is less than a first threshold; and cause the braking systemof the vehicle to activate if the distance between the firstvehicle-mounted subsystem and the second vehicle-mounted subsystem isless than a second threshold. According to a technique, the firstvehicle-mounted subsystem further comprises: a radio-frequencyidentification (RFID) subsystem configured to scan at least one RFID tagexternal to the vehicle to retrieve information stored on the at leastone RFID tag; and wherein the first vehicle-mounted subsystem is furtherconfigured to determine a distance between the first vehicle-mountedsubsystem and the control signal interface subsystem based on theinformation stored on the at least one RFID tag. The firstvehicle-mounted subsystem may be configured to substantiallycontinuously receive information relating to speed of the first vehicle;and the first vehicle-mounted subsystem may determine a changingdistance between the first vehicle-mounted subsystem and the controlsignal interface subsystem based on the information stored on the atleast one RFID tag and the information relating to speed of the firstvehicle. According to one technique, the system includes an access pointexternal to the vehicle. The first vehicle-mounted subsystem is furtherconfigured to: store data relating to prior behavior of the vehicle; andcommunicate the data relating to prior behavior of the vehicle with theaccess point.

Certain embodiments of the present technology provide for avehicle-mounted system for interfacing with a brake loop of a vehicle,wherein the vehicle-mounted system comprises: a switch including a firstcontact configured to connect to a first side of the brake loop and asecond contact configured to connect to a second side of the brake loop;and at least one processor in electrical communication with the switch.The at least one processor is configured to: automatically determine abraking event without receiving information about a status of anoperator-controlled actuator; open the switch upon an occurrence of thebraking event, thereby electrically disconnecting the first contact fromthe second contact; and close the switch upon an expiration of thebraking event, thereby electrically connecting the first contact withthe second contact. According to one technique, the at least oneprocessor is further configured to cause an alert to be generated uponoccurrence of the braking event. According to another technique, the atleast one processor is configured to determine the expiration of thebraking event based on a change in status of an operator-controlledinput.

Certain embodiments of the present technology provide for a system forvehicle speed management, wherein the system comprises: a control signalinterface subsystem; and a vehicle-mounted subsystem. Thevehicle-mounted subsystem is configured to: communicate with the controlsignal interface subsystem to receive information corresponding to astatus of the control signal; determine a rule for behavior of thevehicle according to the information corresponding to the status of thecontrol signal; and observe operation of the vehicle to evaluatecompliance with the rule. According to one technique, the rulecorresponds to the status of the control signal being at least one ofred, double red, yellow, or double yellow. According to anothertechnique, the rule specifies a stop-time duration for the vehicle. Therule may specify a speed for the vehicle. The rule may specify a maximumspeed for the vehicle after an expiration of the stop-time.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a block diagram of a rail control system for enforcingseparation of rail vehicles on a railroad track in accordance with atleast one embodiment of the present technology.

FIG. 2 shows an overhead view of a rail vehicle on a rail line equippedwith a separation control system in accordance with at least oneembodiment of the present technology.

FIG. 3 shows an example of an integrated signal control point used inaccordance with at least one embodiment of the present technology.

FIG. 4 is a block diagram of a vehicle mounted control system used inaccordance with at least one embodiment of the present technology.

FIG. 5 is a block diagram of a collision avoidance system used inaccordance with at least one embodiment of the present technology.

FIG. 6 shows a rail vehicle traveling on a rail line, the vehicleequipped with a control system in accordance with at least on embodimentof the present technology.

FIG. 7 is a flow diagram of a method for determining the speed andlocation of a rail vehicle on a railroad track in accordance with atleast one embodiment of the present technology.

FIG. 8 is a flow diagram of a method for enforcing rail vehicleadherence to control signals in accordance with at least one embodimentof the present technology.

FIG. 9 illustrates a block diagram of a vehicle mounted control systemused in accordance with at least one embodiment of the presenttechnology.

FIG. 10 illustrates a block diagram of a control signal interfacesubsystem in accordance with at least one embodiment of the presenttechnology.

The foregoing summary, as well as the following detailed description ofcertain techniques of the present application, will be better understoodwhen read in conjunction with the appended drawings. For the purposes ofillustration, certain techniques are shown in the drawings. It should beunderstood, however, that the claims are not limited to the arrangementsand instrumentality shown in the attached drawings.

DETAILED DESCRIPTION

The present disclosure generally relates to rail vehicle control systemsand methods. More specifically, the present disclosure describes systemsand methods for enforcing observance to rail signals, for enforcing railspeed limits, for controlling and enforcing rail vehicle separation onrailroad lines, or for temporary speed restriction enforcement forrailway workers or degraded rail conditions, for example, on light raillines.

The present disclosure relates to systems and methods that control raillines. The present disclosure also provides technology that providesinformation about the location and traveling speed of trains on arailroad track. For example, the present technology provides systems andmethods for alerting a vehicle operator when the rail vehicle isapproaching a control signal at an unsuitable rate, and forautomatically braking such vehicles. The present disclosure can be used,for example, in connection with public transit (e.g., light rail linesor commuter lines). The present disclosure, however, is by no meanslimited to public transit, and may be adapted for use with anycombination of vehicles and/or control signals. The present disclosurealso provides systems and methods for enforcing rail speed limits(whether temporary or permanent) and for alerting a vehicle operatorwhen the rail vehicle is exceeding a rail speed limit.

Light rail systems typically employ rail vehicles that are manuallycontrolled by operators located in the control cabs. Railroads canachieve safe separation between these rail vehicles can by providingvisual cues, for example, visual signals observable by a rail vehicleoperator. For example, signal control points and/or reporting stationslocated about a railroad track (e.g., alongside a railroad track) canprovide the visual signals used to control the rail vehicle operationand separation. The signal control points can generate signals, forexample, by producing lights of varying colors or audible sounds. Forexample, a signal control point can provide red, yellow, and greenlights that signal a train operator whether it is safe to proceed to thenext signal, whether the train operator should stop (e.g., by displayinga red light), or whether the train operator should proceed with cautionor at a slower speed (e.g., by displaying a yellow light).

Unfortunately, human error, equipment error, and/or faulty signalingissues, can result in occasional failure to properly communicate andfollow important signals. For example, operators may fail to respond ina timely manner to a signal, or a signal change on the rail track.Additionally, visibility conditions may cause a vehicle operator tomisread, or fail to read a signal along the rail track. Such misreadsignals can result in collisions and other accidents that can havecatastrophic effects. Because rail vehicles are massive objects thatoperate at high speeds, even the slightest impacts and collisions cancause significant damage to people and property, both on the railroadtrack and vehicles, and in the nearby areas. This is particularly so inhigh areas of high population, for example, in urban areas that employmass-transit systems in close proximity to pedestrian areas and otherbuildings.

To address these and other issues, the present technology introducesprotective systems and features that provide safeguards against thesepotential accidents. For example, the present technology providessystems, methods, and features that can detect when a rail vehicle isapproaching or passing a signal control point that is indicating for thevehicle to stop, slow down, or proceed with caution. The presenttechnology also provides systems that can automatically brake or reducethe speed of such vehicles.

The present disclosure also describes systems and methods that detectthe presence of a rail vehicle on the same rail track and the distancebetween the vehicles. In this manner, the technology can effectivelywarn the operator or even automatically brake the vehicle when thedistance between vehicles has broached an acceptably safe value. Thesafe separation distance may be variable according to, for example, thespeed of each vehicle and the relative closing speed of the vehicles.

The present disclosure also describes systems and methods that determinewhether the rail vehicle is operating in excess of the rail speed limit.In this manner, the technology can effectively warn the operator,automatically brake the rail vehicle, or otherwise control the railvehicle so that it operates within the rail speed limit.

The present technology also provides systems and methods that allow arail vehicle (or a rail vehicle operator) to determine the location,operating track, and speed of a rail vehicle, and to communicate thatinformation to a rail network. In particular, the present technologyprovides systems and methods that allow for the determination of railvehicle location and speed without the use of GPS technology. Thisfeature can be effective, for example, in subterranean subway tunnelswhere trains do not have an ability to communicate with satellitestransmitting GPS signals.

The present technology utilizes a variety of functionalities andtechnologies to monitor, control, and enforce separation between railvehicles on a rail track. For example, in some embodiments, the presenttechnology combines ranging technology such as ultra-wideband (“UWB”)ranging, RFID tags and detectors, an ad hoc wireless network betweenvehicles and control signal control portions, and a wireless or wireddata collection system.

In some embodiments, the present technology can utilize a collisionavoidance system, such as that disclosed by U.S. patent application Ser.Nos. 13/474,428 and 14/252,987. U.S. patent application Ser. Nos.13/474,428 and 14/252,987, which are incorporated by reference, describea system that allows rail vehicles to communicate to determine theseparation distance between vehicles.

The present technology can provide a transponder sensor module and/or anUWB system mounted on one or more trains or rail vehicles and can alsobe integrated into signal control points and/or reporting stationslocated along a railroad track (e.g., a signal control point located atthe side of the tracks). In this manner, the transponder sensor modulecan determine a distance between the object upon which the transpondersensor module is mounted and another transponder sensor module mountedon another object (for example, another rail vehicle or signal controlpoint). If the rail vehicles violate a pre-set separation distance, or acontinuously calculated distance given the current vehicle speed and/orrelative closing speed, as calculated by the transponder sensor module,the present technology can then initiate an auto-brake function to slowthe offending vehicle or vehicles in order to maintain a safe distanceamong rail vehicles on a common railroad track.

The present technology can use time of flight techniques, as describedin, for example, U.S. patent application Ser. Nos. 13/474,428 and14/252,987 to detect a distance between rail vehicles and/or betweenrail vehicles and other objects, such as signal control points and/orreporting stations. For example, in some embodiments of the presenttechnology, signal and/or reporting stations located along a railroadtrack can be equipped with collision avoidance systems, transpondersensor modules, UWB systems, and/or other ranging technology or radionetwork signaling devices. In this manner, the rail vehicles cancommunicate with the signal control points to alert the vehicleoperators when the rail vehicle is approaching a signal control point,and the signal that the station is currently indicating. For example,the present technology can warn the vehicle operator that the railvehicle is approaching a signal control point indicating a “stop”signal, and that the operator should begin to reduce the speed of thevehicle.

Certain embodiments also provide an RFID system, which can comprise anRFID reader or reader head mounted on the train. The RFID system canalso include RFID tags (e.g., active and/or passive RFID tags), whichcan be mounted at locations on, along, or around the railroad track. Forexample, the RFID tags can be mounted on the rails or ties of therailroad track, or alternatively, on structures adjacent to the track.The RFID tags can be individually serialized for identificationpurposes, and available for reference or look-up in a database. Inaddition, the tags may be programmed with specific data, such as a speedlimit, track number, or distance to an associated signal, for example.In this manner, each RFID tag can be associated with a location, so thatwhen the serialized RFID tag is read by the RFID reader, the system canhave knowledge of the location of the rail vehicle upon which the RFIDreader is mounted. Moreover, providing multiple RFID tags mounted on therailroad tracks allows the system to calculate the rail speed using thedistance and time between successively read RFID tags. The RFID-basedtechnique for calculating speed may be a supplemental, backup speeddetection means. Other, potentially primary means of speed determinationmight be GPS, vehicle-mounted wheel speed sensor, and/or the change indistance and time to fixed ranging transducers.

In some aspects, the RFID system can also identify or determine aspecific railroad track that it is operating upon. This feature can beparticularly useful when the rail vehicle is traveling on a railroadtrack that operates in close proximity to a parallel railroad track. Forexample, if two trains are equipped with the collision avoidance systemand approaching each other on parallel tracks, by using the RFID system,a rail vehicle or control system can determine that the two vehicles donot pose a collision threat, and therefore avoid false alarms andunnecessary auto-braking can be avoided. That is, by readingindividually serialized or individually programmed RFID tags located onthe track itself, the present technology allows for the identificationof the specific track or line that the vehicle is traveling on,providing an ability to ignore or bypass unnecessary or invalidcollision alerts.

By using the RFID system, the present technology enables a trainlocation to be tracked with an accuracy greater than that allowableusing only GPS methods. Conversely GPS technology does not have theresolution or accuracy necessary to determine a particular rail trackthat a vehicle is traveling upon, particularly when there are severalparallel rail tracks located in close proximity to one another. In thismanner, the present technology provides a system that can determine andbe aware of the particular operating rail track for each vehicle, sothat real collision threats can be determined, and other non-threateningsituations, like an upcoming vehicle on a parallel rail track, can beignored.

In some embodiments, the RFID system can also monitor a specific trainposition when the train is located in areas where conventional GPSpositioning navigational aids are inoperative, such as tunnels andsubways, for example. By reading each RFID tag's serialization code, oralternatively, a programmed mile-marker value, a specific location ofthe train can be determined. This information can then be wirelesslytransmitted over to a supervisory component, for example, via a wired orwireless communication network, for further processing.

The data collection system can comprise an on-board data storage devicecapable of periodically sending data via wired or wireless transmission,for example, to or through a supervisory component. In this manner, thedata collection system can communicate with a rail network to provideinformation about the rail vehicle location and speed, and to obtaininformation pertaining to the location and speed of other vehicles onthe rail track. The data collection system can also maintain andtransmit information relating to rail vehicle warning (e.g., collisionalert) history, maintenance logs, and other related vehicle and trackinformation. For example, the information can be transmitted to a railnetwork by communicating with communication modules located on reportingstations or signal control points located along the rail line. That is,the rail vehicle can communicate wirelessly with a reporting station totransmit and receive relevant vehicle information as the rail vehiclepasses the reporting station on the track. The information can beassimilated into a database on the rail network and/or the rail vehicledata collection system for future analysis. In some embodiments theinformation can be used as a platform for generating automated alertswhich can be sent out over a cell network, or other data stream.

In some embodiments, the present technology functions by independentlymonitoring the state of track block and switch control signals. Forexample, if a vehicle is approaching a signal control point indicating ared (i.e., stop) signal, the present technology can notify the operatorof the vehicle that the red signal is approaching via an audible tone, avisual indication, and/or continuously provide an updated distance tothe red signal to help ensure that the operator is aware of the stopindication. In some embodiments, if the vehicle operator fails to stopthe in an appropriate time or distance relative to the red signal, thetechnology can apply vehicle brakes to slow or stop the vehicle.

The present technology also provides systems and methods that canmonitor the separation distance between equipped rail vehicles, andapply safeguards to assure that the vehicle operators are warned ofpotential collision threats, and/or apply automatic stopping and brakingof the vehicles where a collision may be imminent. For example, theacceptable separation distance may be automatically varied by thissystem in response to vehicle speeds, the grade of the track, and/ortrack condition directives (a we rail condition, for example, wouldresult in extended stopping distances).

The present technology can accommodate the diverse range of operating,weather, and ambient temperature conditions in a variety of locationsand circumstances. For example, the present technology can account forvarious weather conditions (e.g., ice, rain, extreme temperatures, etc.)and other locations and/or circumstances that add variability to railtravel, such as time-of-day or traffic volume. For example, the presenttechnology can operate with rail vehicles operating on street rails thatmust take automobile traffic and various nearby fixed obstructions intoaccount. The present technology can also operate with subway vehicles orin subterranean tunnels that have visibility issues and may not haveaccess to GPS technology. The present technology can also operate inrail conditions that include sharp curves, closely spaced paralleltracks and track switches, or multiple rail intersections or crossoverswitches.

Certain embodiments of the present technology are shown by way of thefigures included with the present application. For example, FIG. 1 is ablock diagram of a rail vehicle separation control system 2 inaccordance with one or more embodiments of the present technology. Therail control system 2 can include a vehicle mounted control system(“VMCS”) 10, which can be, for example, mounted or installed on a railvehicle such as a train or subway car. In some instances, there may bemore than one VMCS 10 mounted on a single vehicle (such as anarticulated vehicle, where wiring between control systems is problematicor expensive). In some embodiments, the system 2 can comprise multipleVMCS's 10, mounted on several rail vehicles. The VMCS's 10 mounted onvarious rail vehicles can be configured to communicate with one anotherin order to determine the speed of the vehicles, and the relativedistance between the vehicles, for example.

The system 2 can also comprise one or more reporting stations 30 locatedalong a railroad. The reporting stations 30 can be located at orintegrated with, for example, signal control points or other objectspositioned at fixed positions along a railroad track. The reportingstations 30 can include a communication mechanism that allows the railvehicles and/or the VMCS 10 installed on the rail vehicles to exchangedata and information, and otherwise communicate with the reportingstations 30. For example, the reporting stations 30 can includetransceivers that allow the reporting stations to send and receiveinformation via Bluetooth, WiFi, radio signals, cellular signals, UWB,peer-to-peer networks, microwaves, infrared signals, lasers, ultrasonicsignals, electromagnetic induction signals, or other modes of wirelesscommunication.

The reporting station 30 can also communicate and exchange informationwith a rail network 50. For example, the reporting station can be inwireless or wired communication with a rail network 50 that manages andmaintains information relating to the speed and location of the railvehicles connected to the network 50, as well as other information aboutthe rail tracks and present weather conditions, for example. The railnetwork 50 can manage and control railroads and tracks in severallocations or geographical areas. In some embodiments, the rail network50 can manage and maintain railroad information pertaining to allrailroad tracks in a region, a state, a country, a continent, or theworld, for example.

Information from the VMCS 10 mounted on the rail vehicles cancommunicate with the network 50 via the reporting stations 30 such thateach vehicle can be aware of the location of other vehicles travelingalong the railroad, their speeds, weather conditions, railroadconditions or situations (e.g., steep grades, approaching sharp curves,rail crossings, or stations), and other information that can be usefulto ensure safe and efficient rail transportation. In some embodiments,the VMCS 10 can communicate directly with the rail network 50 via awireless communication mode without the use of a reporting station.

The rail control system 2 can also include one or more RFID tags 20mounted at locations along a railroad track. For example, the RFID tags20 can be mounted on the railroad rails or the ties of the railroad. Insome embodiments, the RFID tags 20 can be mounted in other locations,for example, on the wall of a tunnel, on the ground, or on poles orstakes located along the railroad track. In this manner, the VMCS (whichmay include an RFID reader) can read the RFID tags 20 located along therailroad track to obtain information about the location, operatingtrack, track speed limit, and/or speed of the vehicle.

FIG. 2 shows an overhead view of a rail vehicle 5 on a railroad lineequipped with a rail vehicle separation control system in accordancewith at least one embodiment of the present technology. FIG. 2 depictstwo railroad tracks 3 and 4 running parallel to one another, and a railvehicle 5 traveling along one railroad track 3. Each of the tracks 3 and4 has a plurality of RFID tags 20 located on the railroad ties of thetrack. As shown in FIG. 2, the RFID tags 20 are positioned about everysix ties; however, in some embodiments, the RFID tags can occur withmore or less frequency as necessary for accurately determining thespeed, track, and location of the rail vehicles 5. In some embodiments,the RFID tags can be installed more frequently, for example, one RFIDtag on every tie, or on every second, third, fourth, or fifth tie.Alternatively, the RFID tags can be installed less frequently, such asone RFID tag on every ten, 20, 30, 50, or 100 railroad ties. As anotherexample, RFID tags could be located at a distance prior to signals thatwould allow a train at the highest speed to stop before the signal ifbraking began at the RFID tag (plus some safety margin), as well as oneither side of switches to indicate the track segment on which the trainis now operating. There may also be redundant tags at those locations.

Where the RFID tags are positioned closer together and occur withgreater frequency, the system can detect the location and speed of therail vehicle 5 with greater accuracy. For example, where the RFID tagsare placed close enough together so that a slower moving rail vehiclecan detect several RFID tags per second, the separation control systemcan continually determine and calculate the location and speed of thevehicle with the passing and detection of each RFID tag. However, RFIDtags that are too close together may not be distinguishable by a railvehicle traveling at a high rate of speed, and may therefore result in aless accurate speed determination. Conversely, where the RFID tags arelocated farther apart, the system may be unaware of the precise locationand speed of the rail vehicle 5 in between the RFID tags, but thesufficient separation can assure that each RFID tag is properly readableand distinguishable from the others. Accordingly, in some embodiments,the RFID tags are placed sufficiently close together so as to accuratelyprovide rail vehicle location and speed information, while also beingsufficiently spaced to ensure that each RFID tag can be properlydetected and distinguished by the VMCS 10 on the rail vehicle 5.

FIG. 2 also shows a reporting station 30 located along the railroadtrack 4. As shown, the reporting station 30 is located to the side ofthe railroad tracks in close proximity to the tracks. In this manner,the reporting station can be visible to a vehicle operator on a passingrail vehicle. In some embodiments, the reporting station 30 can transmitand/or receive information from a passing rail vehicle 5 via a VMCS 10,for example. The reporting station 30 can then transmit rail vehicleinformation and/or other information (e.g., information regardingweather conditions) to the rail network. For example, the reportingstation 30 can include a transponder sensor module adapted tocommunicate with the transponder sensor module installed on the railvehicle 5.

The reporting station 30 can also be, for example, a signal controlpoint that generates signals viewable by an operator of the rail vehicle5. For example, the reporting station 30 can provide signals in the formof various colored lights that provide information and/or instructionsto an operator of a passing rail vehicle 10. The reporting station 30may also communicate information (e.g., signal state or other types ofinformation known to the reporting station 30) to the VMCS 10. FIG. 3shows an example of a reporting station that operates as an integratedsignal control point 40 in accordance with the present technology. Thesignal control point 40 comprises wiring 31 that can connect the signalcontrol point 40 to a power source, a processor, and/or othercontrolling equipment. The signal control point also comprises one ormore signal lights 32, which can be, for example, LED signal lights.

The signal lights can operate as a signal where the illumination ofcertain lights indicates a certain railroad track status, aninstruction, or other information. For example, when a red light isilluminated, the signal control point can be indicating that theoperator of the passing rail vehicle 5 should stop the vehicle 5. Agreen light can indicate that the rail vehicle 5 can proceed to travelalong the track at the authorized speed. And a yellow light canindicate, for example, that the rail vehicle operator should proceedwith caution, or be prepared to stop at an upcoming signal. In someembodiments, the signal control point can include other signals, forexample a double red signal (or a red over red signal), which canindicate, for example, that the vehicle should stop and stay. In thismanner, only an “authorized person,” such as an inspector or higherranking officer can hand flag a car through a double red signal. In someembodiments, the signal control point can also display a double yellow(or a yellow over yellow) signal, indicating that the operator shouldstop, and then proceed at a restricted speed with caution, for example,because an upcoming station may be occupied by a train.

The signal control point can also comprise a communication link 35,which allows for communication and/or information exchange with passingrail vehicles and a rail network 50. The communication link 35 can be,for example, a component of the AURA™ system provided by Metrom Rail,which is described in U.S. patent application Ser. Nos. 13/474,428 and14/252,987 that are incorporated by reference. The communication link 35can communicate, for example, with a VMCS 10 mounted on a passing railvehicle 5. In this manner, the communication link 35 can be used toexecute warning signals as a rail vehicle 5 is approaching the signalcontrol point 40 and/or to execute other functionality, such asautomatic braking when the rail vehicle 5 is not heeding the signalcontrol point 40 instructions. In some embodiments, the communicationlink 35 can be, for example, a transponder sensor module.

Referring again to FIG. 1, the rail vehicle separation control system 2comprises a VMCS 10 that is mounted on a rail vehicle, and communicates,either directly or indirectly, with a rail network 50. The VMCS 10 alsosenses RFID tags 20 that are located along a railroad track. Oneembodiment of the VMCS 10 is depicted in greater detail in FIG. 4.

FIG. 4 is a block diagram of a VMCS 10 that can be used in connectionwith the rail line vehicle separation control system of the presenttechnology. The VMCS 10 can comprise one or more components that can bemounted, connected, or otherwise installed on a rail vehicle. Forexample, the VMCS 10 can be a single module comprising one or morecomponents that and installable at a location on a rail vehicle.Additionally and/or alternatively, the VMCS 10 can comprise one or moremodules, each module comprising one or more components and beinginstallable at one or more locations on a rail vehicle. In someembodiments, the VMCS 10 is adapted to communicate with one or moreVMCS's 10 installed on another rail vehicle operating on the samerailroad track.

In certain embodiments, the VMCS 10 comprises a collision avoidancesystem 100, an RFID reader 200, a data collection system 300 and asupervisory component 500. The VMCS 10 can include, or be in wirelesscommunication with the rail network 50 that manages and maintainsinformation about various rail vehicles and/or other VMCS's installed onvehicles on a railroad track.

The collision avoidance system 100 can be adapted to determine adistance between the rail line vehicle and another rail line vehicleoperating on the same railroad track. For example, the collisionavoidance system 100 can be adapted to communicate with a nearby orproximate rail vehicle operating on the same track. In some embodiments,the collision avoidance system 100 can communicate with at least therail vehicle that is directly in front of it, and the rail vehicle thatis directly behind it on the same railroad track. In this manner, thecollision avoidance system 100 can determine a distance between the railvehicle and the proximate rail vehicles on the same track. In someembodiments, the collision avoidance system 100 can include orincorporate one or more components of AURA™ system and/or the systemdescribed in U.S. patent application Ser. Nos. 13/474,428 and 14/252,987(which have been incorporated by reference in their entireties).

A more detailed view of a collision avoidance system 100 is provided inFIG. 5. FIG. 5 is a block diagram of a collision avoidance system 100,which can include, for example, one or more transponder sensor modules110, one or more antennae 120, an auto-braking system 130, a warningsystem 140 and a processor 150, or central control unit. As disclosedherein, a “processor” may include more than one processors actingtogether to achieve a given function. According to one technique, theprocessor 150 includes a main processor and a safety processor to makethe system more robust and fail-safe.

One or more transponder sensor modules 110 can be located on the railvehicle. According to one technique, one transponder sensor module 110is located on or proximate to the front of the rail vehicle, and anothertransponder sensor module 110 is located on the back of the vehicle.According to another technique, only one transponder sensor module 110is located at a known location on the rail vehicle.

In some embodiments, the transponder sensor module 110 is adapted tosend out a signal and receive a reflective or responsive signal from acorresponding transponder sensor module installed on another railvehicle. The transponder sensor module 110 can send signals using a oneor more technologies and methods. For example, in some embodiments, thetransponder sensor module 110 can be or include a UWB ranging unitconfigured to send UWB radio waves. Additionally and/or alternatively,the transponder sensor module 110 can comprise a transceiver configuredto utilize another communication technology including, but not limitedto, radio waves, lasers, ultrasonic waves, RADAR, or light signals(e.g., infrared signals), that can be reflected or re-sent at adeterminable speed. The transponder sensor module 110 can be used tocommunicate with other transponder sensor modules installed on proximaterail vehicles, for example, by sending radio waves/pulses outward viathe antenna 120 or other transceivers associated with the transpondersensor module 110.

In this manner, a distance between the various transponder sensormodules 110 (and thus, the distance between the rail vehicles upon whichthe transponder sensor modules are installed) can be determined. Bymeasuring how long it takes a wave/pulse or a signal to travel (forexample by reflecting and/or bouncing, or a precisely timed response)between two transceivers, the distance between the transponder sensormodules can be accurately determined. That is, the present technologycan detect the distance between two rail vehicles and/or the distancebetween a rail vehicle and signal/reporting station based on the time ittakes a signal to travel between the transponder sensor modules. Thistechnique may be referred to as “time of flight.” The processor 150 oranother processing unit can be used to determine the distance betweenthe vehicles based on the results of the time of flight.

Consider the scenario in which a transponder sensor module 110 islocated on the back of a first rail vehicle and another transpondersensor module 110 is located on the front of a second rail vehicle. Thefirst rail vehicle is in front of the second rail vehicle. In thisscenario, the time of flight technique can be used to determine thedistance between the two transponder sensor modules 110, and thereforethe distance between the first and second rail vehicles.

Consider, alternatively, the scenario in which there is only onetransponder sensor module 110 on the first rail vehicle and only onetransponder sensor module 110 on the second rail vehicle. The first railvehicle is in front of the second rail vehicle. Given the time of flightand the known length of one or more of the first or second railvehicles, the distance between the vehicles can be determined. Forexample, if the transponder sensor modules 110 are located on the frontof each rail vehicle, the distance between the vehicles would be afunction of the distance between the transponder sensor modules 110 andthe length of the first rail vehicle. As another example, if thetransponder sensor modules 110 are located on the back of each railvehicle, the distance between the vehicles would be a function of thedistance between the transponder sensor modules 110 and the length ofthe second rail vehicle.

In some embodiments of the present technology, the collision avoidancesystem 100 also includes a GPS unit that can be used in combination with(or as a component of) the transponder sensor module to determine aposition (e.g., an absolute position) of the rail vehicle. In thismanner, the present technology can combine GPS functionality with thetime of flight technology to determine a separation distance betweenrail vehicles. The GPS and/or the time of flight technology can serve asredundant systems that assure a separation distance between railvehicles is known even when one of the systems is not effectivelyworking. For example, the GPS unit can be used to ensure that the timeof flight technology is not providing incorrect separation distanceinformation because of reflected signals. Moreover, the time of flighttechnology can be used to observe separation distance in situationswhere the GPS unit is incapable of receiving positioning information,for example, due to issues with satellite connectivity. This can beparticularly useful, for example, for rail vehicles traveling insubterranean tunnels (e.g., subways), where there is limited or noaccess to GPS functionality. The GPS operating frequency may be 1.575GHz. The system may include two GPS receivers, for example, to provideredundancy. GPS information may provide speed data and the vehicledirection of travel. Such data may allow for periodic self-calibrationof the on-board vehicle speed measurement system. This can allow forautomatic compensation of wheel wear (which can otherwise causeexaggerated speed measurements over time). The VMCS 10 may perform theautomatic compensation.

The VMCS 10 may have a speed measurement system which may be distinctfrom the speedometer of the vehicle (prior to installation of the VMCS10). The VMCS 10 may receive information regarding the rate of wheelrotation, and speed may be calculated therefrom. The VMCS 10 may also becapable of determining speed information from GPS information and/orRFID tag scanning rate. It may also be possible to measure speed usingthe UWB time-of-flight data, since this data provides substantiallycontinuous location information over time.

In some embodiments of the present technology, the collision avoidancesystem 100 can operate fully, effectively, and safely without GPStechnology. This is particularly true for subway rail vehicles, whichcan often have limited or no use for a GPS feature.

In some embodiments, the collision avoidance system 100 and/or thetransponder sensor module 110 can communicate with reporting stationsand/or signal control points, such as the signal control point 40depicted in FIG. 3 (for example, via UWB communications). In thismanner, the transponder sensor module 110 may communicate with thecommunication link 35 or another similar component of the signal controlpoint 40 to determine a distance between the vehicle and the signalcontrol point 40.

The VMCS 10 may also implement a second or redundant wireless network.Such a network may improve the robustness of the system. Such a networkmay be of a different type than the first network. For example, thesecond network may be a spread-spectrum network (for example, one thatimplements frequency hopping). Such a network may operate at 2.4 GHz.The second network may transmit information similar to what istransmitted by the first network.

When the collision avoidance system 100 determines that the signalsprovided by the signal control point 40 are not being followed by therail vehicle operator, the processor 150 can operate one or more otherfunctions of the collision avoidance system 100. For example, theprocessor may use the auto-braking system 130 to initiate anauto-braking feature to automatically brake or otherwise reduce thespeed of the rail vehicle. In some embodiments, when the collisionavoidance system 100 determines that the distance between the rail linevehicle and a proximate rail line vehicle operating on the same railroadtrack has come within a predetermined limit, the collision avoidancesystem 100 may initiate the auto-braking feature in order to preventand/or reduce the likelihood of a collision. The processor can then logthe auto-braking action, for example, in the data collection system 300of the VMCS 10.

In some embodiments, the auto-braking system 130 can be adapted toautomatically brake a rail vehicle based on the distance between thevehicle and a signal control point 40, depending on the signal indicatedby the signal control point 40. For example, the collision avoidancesystem 100 can automatically brake the rail vehicle when the collisionavoidance system 100 detects that the rail vehicle is not observing astop signal communicated by the signal control point. In someembodiments, the collision avoidance system 100 may determine that thestop signal is not being observed based on the speed of the rail vehicleand the distance between the rail vehicle and the signal control point.For example, in some embodiments, there can be a safety point located onthe railroad tracks relative to the signal control point, the safetypoint representing the furthest location where rail vehicles can come torest when a stop signal is indicated in order to ensure safe railroadtrack operation. In some embodiments, the safety point can be, forexample, at or around the location of the signal control point. When thedistance between the rail vehicle and the signal control pointapproaches or exceeds a limit where it is no longer possible to bringthe vehicle to a complete stop before the safety point during existingconditions, the auto-braking system 130 can automatically brake thevehicle.

In some aspects of the present technology, the speed and/or distanceused to determine whether or not to apply the auto-braking system 130can vary based on conditions. For example, when the tracks are we oricy, the collision avoidance system 100 may determine that the stopsignal is not being observed at a lower rate of speed and/or distancefrom the signal control point than under normal dry conditions. Incertain embodiments, the collision avoidance system 100 may determinethat the stop signal is not being observed if the rail vehicle passesthe signal control point. In other embodiments, the collision avoidancesystem 100 may determine that the stop signal is not being observed ifthe vehicle operator fails to respond to warnings or other commands fora predetermined period of time, for example.

The auto-braking system 130 does not include the vehicle brakes.Instead, the auto-braking system 130 can be configured to work withbrakes and associated vehicle componentry. The auto-braking system 130can provide one or more outputs that cause existing brakes to be applied(either at 100% of braking force or at some lesser level) or released.

The collision avoidance system 100 can also utilize the warning system140 to initiate a warning signal as the rail vehicle approaches a signalcontrol point 40 or another rail vehicle. The warning system 140 can beoperable to initiate a warning signal indicating that the rail vehicleoperator should decrease the speed of the rail vehicle. In someembodiments, the warning system 140 can operate to initiate a warningsignal as the rail vehicle approaches or passes a signal control pointindicating a stopping signal. Additionally and/or alternatively, thewarning system 140 can be operable to initiate a warning signal when thedistance between the rail vehicle and a proximate rail vehicle is withina predetermined limit. For example, the predetermined limit can be avalue that ensures that the rail vehicle can safely be brought to acomplete stop without colliding with the proximate vehicle. Thepredetermined limit can vary depending on the rail conditions, theweather conditions, and the speed of the rail vehicle and the proximaterail vehicle, for example.

For example, when a rail line vehicle is approaching a signal controlpoint 40 indicating a red light, the warning system 140 can generate anaudible and/or visual warning indicating the approaching signal.Further, the warning system 140 can be configured so that the warningsignal changes, or increases in intensity as the signal is approaching.In some embodiments, a warning signal, or warning alarm can involve acontinuous, alternating audible notification for the vehicle operator,along with an urgent flashing visual indication. In some embodiments,the warning signal can sound continuously until the operator presses anacknowledge button an interface, until the vehicle has come to a stop,or until the condition that caused the alarm has been cleared. In someembodiments, after a warning alarm has been acknowledged, the collisionavoidance system 100 can initiate a reminder alert will soundperiodically (e.g., every five seconds) until the vehicle has come to astop, or the condition that originally caused the alarm has beencleared.

In some embodiments, the collision avoidance system 100 may useauto-braking system 130 and the warning system 140 together. Forexample, when the vehicle passes a red signal without stopping, thecollision avoidance system 100 can alert the vehicle operator using thewarning system 140, log the event description, timestamp, signal state,measured distance to the signal, and the vehicle operating conditionswhen the alarm was sounded. The collision avoidance system 100 can beconfigured such that the warning signal can be quieted if the vehicleoperator presses a confirmation button, but to sound a periodic alertuntil vehicle is stopped or the signal is no longer red. If the vehicledoesn't begin braking within a predetermined distance or time (e.g., 50feet or two seconds of passing the signal control point 40), thecollision avoidance system 100 use the auto-braking system 130 to slowor bring the vehicle to a haft.

In some embodiments, the collision avoidance system 100 can record andlog information about passing signal control points. For example, when avehicle is passing a signal control point 40 indicating a green signal,the auto-braking system 130 may not be used. Rather, the event can belogged with an event description, timestamp, signal state, and vehicleoperating conditions when the signal was passed. Moreover, when thevehicle passes a signal control point 40 indicating a yellow signal, thecollision avoidance system 100 may alert the vehicle operator; log theevent description, timestamp, signal state, measured distance to thesignal, and the vehicle operating conditions when the alert was sounded.

Referring again to FIG. 4, the collision avoidance system 100 operatesin connection with a supervisory component 500, which also communicateswith an RFID reader 200 and a data collection system 300. In someembodiments, the RFID reader 200 can be connected to the collisionavoidance system 100. The data collection system 300 can include, forexample, a data storage device capable storing data and information thatcan be accessible via the supervisory component 500. The data collectionsystem 300 can maintain a log of events, conditions, and rail vehicleinformation, and transmit that data to the rail network 50. The datacollection system 300 can also comprise a database of information thatrelates to the rail vehicle, the rail track, and other rail vehiclesassociated with the rail network 50. Information obtained by thecollision avoidance system 100 and/or the RFID reader 200 can betransmitted to stationary collision avoidance systems (e.g., collisionavoidance systems installed on control signal points), which can in turntransmit the information to a rail network 50 (e.g., a wired network).

The RFID reader 200 can be configured to detect the RFID tags 20 thatare installed or otherwise located along the railroad track. The RFIDreader 200 can be configured to detect active tags, passive tags, orboth. The RFID tags 20 can be serialized such that each RFID tag 20 isdistinguishable from the other. In this manner, each RFID tag 20 can beassociated with information about the location of the RFID tag. RFIDtags 20 may also include or convey information relating to specificinformation about a given RFID tag 20. Such information includes workzone status, speed limit, grade, subterranean track segment, trackreroute, and/or increased stopping distances. Temporary tags 20 may beinstalled to temporarily provide such information to the VMCS 10. Suchinformation can be actually stored in a tag 20, or may be stored in adatabase. The unique identity of the tag 20 may be used to look up suchinformation in a database. Such a database may be stored in the VMCS 10or remotely. A VMCS 10 database may be updated via the rail network 50,for example, through an access point or reporting station 30.

For example, each serialized RFID tag 20 can be referenced in a databaseonce read by the RFID reader 200. The database can be, for example, apart of the data collection system 300. The database can includeinformation pertaining to the location of each RFID tag 20 associatedwith the rail vehicle separation control system 2. In this manner, eachtime the RFID reader 200 detects an RFID tag 20, the VMCS 10 can consultthe database via the data collection system 300 to determine thelocation of the RFID tag 20, and thus, the location of the rail vehicle.Location may also be determined by interaction between a signal controlpoint 30 and a map (for example, one stored in the VMCS 10 or remotely).If the signal control point 30 is known and the distance of the VMCS 10from the signal control point is known, then location can be determined.

In some embodiments, the RFID reader 200 and/or the VMCS 10 can record aspecific time at which each RFID tag 20 has been read. Thus, the speedof the rail vehicle can be determined based on the distance between twoor more RFID tags 20, and the time elapsed between the RFID tag 20detection. In some embodiments, the present technology can include, orcan be interfaced with a speed measurements system on the vehicle (e.g.,the speedometer). In this manner the present technology and the existingspeed measurement system can serve as redundant features to improve thespeed calculation of the vehicle. The system may also include a vehiclewheel speed sensor to independently determine the speed of the vehicle.These other speed determining components (speedometer and/or wheel speedsensor) may be used together with the RFID tag scanning system. Datafrom the speed determining components may be transmitted to other systemcomponents via an ad hoc, decentralized network. As another example,data generated by these other speed sensing components may becommunicated to the rail network 50 similar to how the RFID tag scanningdata is transmitted.

The RFID system (comprising the RFID reader 200 and the RFID tags 20)can also be used to determine the specific railroad track that the railvehicle is traveling on. That is, each serialized RFID tag 20 can beassociated with a particular railroad track such that the VMCS 10 andthe rail vehicle separation control system 2 can be aware of which trackeach rail vehicle is traveling. This can be particularly useful if tworailroad tracks are located parallel to one another and in closeproximity. By reading individually serialized RFID tags located on thetrack itself, the present technology allows for the identification ofthe specific track or line that the vehicle is traveling on, providingan ability to ignore or bypass unnecessary collision warnings orauto-braking processes. The RFID tags 20 may operate in a 900 MHz ISMband.

Using the RFID reader 200 and tag 20 system of the present technology, aVMCS 10 can be aware of the vehicle's location and speed at any timeregardless of its location. The location and speed information can bedetermined even when the rail vehicle is not able to access satellitesand/or GPS functionality. In this manner, the present technology can beused in subterranean tunnels and/or subways to keep all vehicleoperators and rail control systems apprised of the location and speed ofeach vehicle on the network, regardless of its location or access to GPSfunctionality.

The VMCS 10 may actually have several ways of determining speed. Suchways include determining speed by: wheel rotation rate; GPS information;RFID tag 20 scanning; and/or distance ranging over time (for example,using the UWB time-of-flight data over time). This may provideredundancy for robustness and also serve to allow the VMCS 10 toperiodically recalibrate the estimated wheel size (which is used inconjunction with the wheel rotation rate to determine speed).

The supervisory component 500 can be connected remotely and/orwirelessly to the rail network 50. For example, the supervisorycomponent can communicate with the rail network 50 via one or morereporting stations 30 that are installed or otherwise located along therailroad track. For example, when the rail vehicle passes a reportingstation 30, the supervisory component 500 and/or the VMCS 10 cancommunicate information to the reporting station 30, and thus the railnetwork 50 wirelessly. For example, the reporting stations 30 and/or theVMCS 10 can include one or more antennae, receivers, transmitter, and/ortransceivers that allow the reporting stations to send and receiveinformation via Bluetooth, WiFi, radio signals, cellular signals,microwaves, infrared signals, lasers, ultrasonic signals,electromagnetic induction signals, or other modes of wirelesscommunication. In this manner, the VMCS 10 can communicate informationabout the rail vehicle location, speed, separation between proximatevehicles, weather conditions, track conditions, and other relevantinformation to the rail network 50. The rail network 50 can use thisinformation to manage and maintain an entire railway system to ensurethat all rail vehicles on the railway system are operating at safedistances from one another and/or are properly distributed for timelytransit operations.

FIG. 6 shows an image of a rail vehicle 5 traveling on a rail lineequipped with various components of a VMCS 10 of the present technology.The rail vehicle 5 can have a collision avoidance system 100 installedat a location on the front of the rail vehicle 5. An RFID reader 200 canalso be installed at the front end of the rail vehicle 5, so that RFIDtags located on the rails or ties can be read and detected. Otherlocations for the RFID reader 200 include the side, rear, or bottom ofthe vehicle 5. Placing the RFID reader 200 on the bottom of the vehiclemay be particularly effective when RFID tags 20 are located on railties. As shown, the VMCS 10 can be installed on a rail vehicle as amodule that comprises one or more components separate from one another.

In operation, the present technology can be used to control and enforceseparation among rail vehicles. In some embodiments, the presenttechnology provides a system that can detect a distance between the railvehicle and a proximate rail vehicle on the rail track. In someembodiments, the present technology vehicle separation control system isadapted to detect the location of the rail vehicle, the speed of therail vehicle, and the distance between the rail vehicle and theproximate rail vehicle when the rail vehicle is located in asubterranean tunnel. The present technology can include systems thathave an auto-braking system 130 that automatically reduces the speed ofthe rail vehicle when the distance between the rail vehicle and theproximate rail vehicle on the rail track is within a predeterminedlimit. The predetermined limit can be calculated based at least in parton the speed of the rail vehicle. For example, where a rail vehicle istraveling at a high rate of speed, it will take a greater distance tobring the vehicle to a stop. Accordingly, in such a circumstance, apredetermined distance can be relatively high to ensure that the railvehicle can come to a complete stop before colliding with anothervehicle.

Certain embodiments of the present technology relate to systems mountedor mountable on a rail vehicle. Moreover, some embodiments of thepresent technology relate to rail vehicle separation control systemsthat include or incorporate a VMCS 10 in addition to other features,including but not limited to: a rail network 50 maintaining informationrelating to the location and speed of rail vehicles on the railroadtrack; one or more of serialized RFID tags 20 mounted at locations alongthe railroad track; and one or more reporting stations located along therailroad track, the reporting station operable to communicate with therail network 50. The VMCS 10 can obtain vehicle information relating tothe railroad track that the rail vehicle is traveling upon and the railvehicle location based on the GPS information and/or serialized RFIDtags 20 detected by the RFID reader 200. Speed may be determined bythese subsystems and/or by the wheel rotation rate. The VMCS 10 can thencommunicate the vehicle information to the rail network 50. In someembodiments, the reporting station can be a signal control pointoperable to display signals viewable by an operator of a rail vehicletraveling along the railroad track.

Certain embodiments of the present technology also provide methods ofenforcing rail vehicle separation. In some embodiments, the methodsinvolve determining the speed and location of a rail vehicle travelingalong railroad track.

FIG. 7 is a flow diagram 700 depicting a method for determining thespeed and location of a rail vehicle in accordance with at least oneembodiment of the present technology. The method may be performableusing the structures and functions described herein. The stepsillustrated in the flow diagram 700 may be performable at least in partby one or more processors, such as the processor(s) in the VMCS.Furthermore, the steps illustrated in the flow diagram 700 may beperformable in a different order, or some steps may be omitted accordingto design and/or preferences. The steps illustrated in the flow diagram700, or a portion thereof, may be performable by software, hardware,and/or firmware. The steps illustrated in the flow diagram 700, or aportion thereof, may also be expressible through a set of instructionsstored on one or more computer-readable storage devices, such as RAM,ROM, EPROM, EEPROM, flash memory, optical disk, magnetic disk, magnetictape, and/or the like.

As shown in FIG. 7, the flow diagram 700 includes, at step 710,detecting a first serialized RFID tag located along a railroad track.The first serialized RFID tag can be detected, for example, with an RFIDreader mounted on the rail vehicle. The first serialized RFID tag canhave a serialized identifier, for example, that corresponds to locationinformation of the RFID tag along the railroad track. In this manner, aVMCS can reference the serialized RFID tag in a database to obtaininformation about the RFID tag's (and thus the rail vehicle's) locationalong the railroad track. In some embodiments, at step 710, the methodmay include noting a time (e.g., a first time n) that the serializedRFID tag was read.

At step 720, a second serialized RFID tag is detected using the RFIDreader. The second RFID tag can also have a serialized identifier thatcan be referenced in a database to obtain information about the RFIDtag's location along a railroad track. In some embodiments, at step 720,the method may include noting a time (e.g., a second time t2) that theserialized RFID tag was read.

At step 730, the first and/or second serialized RFID tag are referencedin a database. In this manner, at step 730, information can be obtainedabout the location of the rail vehicle at the first time n, and thelocation of the rail vehicle at the second time t2, based on the timesthat the first and second RFID tags were read by the RFID reader. Insome embodiments, the RFID tags may be referenced by a latitude andlongitude coordinate system. Additionally and/or alternatively, in someembodiments, each RFID tag may be associated with location informationthat is referenced with respect to the railroad tracks. For example, theRFID tags can be identified as a certain distance (e.g. 5 miles, 2390.81feet) from a reference point, such as a rail station, a reportingstation, railroad tie, etc.

At step 740, the flow diagram 700 can include determining vehiclelocation information. For example, at step 740, the flow diagram 700 candetermine a precise or approximate vehicle location based on thelocation information associated with the RFID tags recently read by thereader based on the information referenced in the database. In someembodiments, the location information can be based on geographiccoordinates (e.g., latitude and longitude coordinates) or a positionrelative to a reference point, for example. As another example, locationinformation may correspond to a mile-marker value (e.g., 21.3 miles).

At step 750, the flow diagram 700 determines the vehicle speedinformation. The vehicle speed information can be based on the locationsof the RFID tags read by the RFID reader, the distance between the RFIDtags, and the times at which the RFID tags were read. In this manner themethod can determine and continually update the speed of the railvehicle by dividing the distance between two detected RFID tags by thetime elapsed between the points when they were detected. In certainembodiments, this can provide a validation, or redundancy for theon-board speed measurement system (e.g., the speedometer). That is, theRFID reader can be used as a cross-check to the on-board speedmeasurement system. If it is determined that there is a significantdisagreement over the course of multiple measurement cycles, thetechnology may record a fault and notify the rail network. In this wayany problems can be diagnosed and repaired.

The rail vehicle location and speed information can be logged, stored,and/or maintained in a database. For example, in some embodiments, therail vehicle speed and location information can be logged in a datacollection system that is a component of the VMCS as rail vehicleinformation.

In some embodiments the method also involves determining the distancebetween the rail vehicle and another rail vehicle. For example, in someembodiments, a VMCS can be used to send signals, and receive signalsfrom other VMCS devices mounted on proximate rail vehicles. In thismanner, a time of flight technology can be used to determine aseparation distance between the rail vehicles. In some embodiments, aGPS unit can be used to determine the separation distance between two ormore rail vehicles. And in some embodiments, the method may use acombination of time of flight and GPS technology to more accuratelydetect and determine a distance between rail vehicles operating on acommon rail track. The separation distance information can also belogged, stored, and maintained in a database, for example, a datacollection system component of a VMCS as rail vehicle information.

In some embodiments, other information can be obtained and recorded bythe VMCS. For example, information about weather conditions, rail trackconditions, rail track problems or issues, signal control pointconditions, instructions, or issues, and/or passing rail vehicle issuescan be detected. This information can also be logged, stored, andmaintained in a data collection system component of a VMCS as railvehicle information.

Logged information may be stored at the VMCS in non-volatile memory.Logging may involve two event categories: incident and activity.Incident logging may record catastrophic events (for example, acollision), whereas activity logging may be used for all other events(for example alarm-generating events or braking events).

At step 760, the method communicates rail vehicle information to a railnetwork. The information can be communicated, for example, bytransmitting information from a VMCS to a reporting station locatedalong a rail track.

In some embodiments of the present technology, the method can involvegenerating a signal to alert a vehicle operator of an approachingstopping signal, an approaching vehicle, or of other noteworthy events,in particular, events that could result in a collision or accident suchas excessive speed. In some embodiments, the present technology mayautomatically brake or reduce the speed of a rail vehicle. For example,in some aspects, methods could involve initiating an auto brake featurethat automatically applies brakes to reduce the speed and/or stop therail vehicle.

FIG. 8 is a flow diagram 800 depicting a method for enforcing railvehicle adherence to rail control signals in accordance with at leastone embodiment of the present technology. The method may be performableusing the structures and functions described herein. The stepsillustrated in the flow diagram 700 may be performable at least in partby one or more processors, such as the processor(s) in the VMCS.Furthermore, the steps illustrated in the flow diagram 700 may beperformable in a different order, or some steps may be omitted accordingto design and/or preferences. The steps illustrated in the flow diagram700, or a portion thereof, may be performable by software, hardware,and/or firmware. The steps illustrated in the flow diagram 700, or aportion thereof, may also be expressible through a set of instructionsstored on one or more computer-readable storage devices, such as RAM,ROM, EPROM, EEPROM, flash memory, optical disk, magnetic disk, magnetictape, and/or the like.

As shown in FIG. 8, the flow diagram 800 includes, at step 810,communicating a control signal via a signal control point. For example,the signal control point can communicate a “stop” signal by presenting ared light, a “proceed” signal by presenting a green light, or a “proceedwith caution” signal by presenting a yellow light. In some embodiments,the control signal may include a speed limit for the rail vehicle. Thecontrol signal can be communicated to passing rail vehicles, to a railnetwork, and to other signal control points, for example, via wirelesscommunication devices.

At step 820, the flow diagram 800 detects a distance between the railvehicle and the signal control point. For example, the flow diagram 800can employ a collision avoidance system to detect a distance between therail vehicle and the signal control point using time of flighttechniques. That is, in some embodiments, the step of determining adistance can be based on the time it takes a signal to travel betweenthe transponder sensor modules on the rail vehicle and signal controlpoint, for example. The collision avoidance system can comprise, forexample, one or more transponder sensor modules installed on each of therail vehicle and the signal control point.

In certain embodiments, at the step 830, the flow diagram 800 caninclude determining whether the rail vehicle is approaching a signalcontrol point indicating or communicating a control signal. A controlsignal may be a “stop” signal or a signal communicating a speed limitfor the rail vehicle. For example, the flow diagram 800 can use acollision avoidance system to detect a distance between the rail vehicleand a signal control point to determine whether the signal control pointis indicating a “stop” or other signal. For example, the rail vehiclecan communicate with the signal control point and/or a rail networkusing a supervisory component to determine the signal that the signalcontrol point is currently indicating. If it is determined at step 830that the rail vehicle is not approaching a signal, the method can cycleback to step 820, for example, and continue detecting the distancebetween the rail vehicle and upcoming signal control points. If it isdetermined that the upcoming signal control point is indicating a“proceed” signal, then the flow diagram 800 can allow the vehicle toproceed past the signal without any warning or suggestion to slow thevehicle.

If it is determined that the signal control point is indicating a “stop”signal, or any other signal suggesting that the rail vehicle reduce itsspeed (such as a speed limit signal), then the flow diagram 800 canproceed to step 840 and generate a warning signal. For example, step 840can involve generating a warning signal via a warning system componentof a collision avoidance system on the rail vehicle. In certainembodiments, the warning system can issue a series of beeps or alarmsthat will continue until the vehicle operator acknowledges the signal,for example, by pressing a button or communicating a signalacknowledgement, or until the vehicle reduces its speed or comes to astop. In certain embodiments, the warning signal can be a progressivewarning signal that increases in volume, duration, repetition rate,and/or frequency as the signal control point draws nearer. In thismanner, the warning signal can be used as a failsafe to ensure that thevehicle operator recognizes the signal and thereby take steps to slowand/or stop the vehicle. Warning signal(s) may also be visual.

At step 850, the flow diagram 800 determines whether the vehicle isobserving the control signal. For example, at step 850, the flow diagram800 can determine, based on factors such as the vehicle speed, vehiclelocation relative to the rail signal, and rail track conditions whetherit is possible for the vehicle to come to a stop in a safe manner. Forexample, given the speed of the vehicle, the track conditions, and thedistance to the signal control point, an appropriate braking distance orspeed reduction distance may be determined. This is a distance thatallows for safe braking by the time the vehicle reaches the signalcontrol point. If the vehicle does not begin slowing down at anappropriate rate once the distance is reached, then it can be determinedthat the vehicle is not observing the control signal.

In some embodiments, step 850 may determine that the vehicle is notobserving the stop signal when the vehicle passes the signal controlpoint (or any predetermined point along the rail track) at any speed. Ifit is determined that the vehicle is indeed observing the stop signal,the flow diagram 800 can cycle back to step 830, 820, and/or 810 anddepending on the location of the train and the conditions of the signalcontrol points. In some embodiments, step 850 may determine that thevehicle is not observing the speed limit signal when the vehicle passesthe signal control point (or any predetermined point along the railtrack such as an RFID tag).

According to one technique, a database of trackside RFID tags (each witha unique ID) is maintained. Each RFID tag (or a portion thereof) has anassociated speed limit that is stored in the database. As the vehiclereaches an RFID tag, the speed of the vehicle is checked against theappropriate speed indicated by the database for the given RFID tag. Ifthe vehicle speed exceeds the given speed limit for that tag, then itcan be determined that the vehicle is not observing the speed limit. Thedatabase may store different limits for each RFID tag according to otherconditions such as weather, construction, or time-of-day. Alternatively,the database may store one or more limits for each RFID tag that can beadjusted according to such other conditions. For example, if the trackis we or there is rain, a speed limit value for an RFID tag may bereduced by a percentage, such as 20%. The database may be stored locallyon the vehicle or remotely at a rail control system.

According to another technique, the distance of an approaching vehicle(for example, another vehicle in front of the vehicle) may bedetermined. The rate of change of the distance may also be determined.Based on the distance, the rate of change of the distance, the speed ofthe vehicle, the speed of the other vehicle, and/or the trackconditions, it may be determined that there is a risk of the vehiclescolliding. Accordingly, a warning (an alert may be a type of warning)may be generated.

If a warning is being generated, the failure of the vehicle to observecontrol points, speed limits, or recognize an approaching vehicle mayescalate the level of the warning—e.g., causing a louder warning or abrighter, different colored warning (for example, go from yellow tored). If a warning is not being generated, then failure to observecontrol points or speed limits may cause a warning signal to beinitiated.

If it is determined at step 850 that the rail vehicle is not observingthe control signal, speed limit, or approaching vehicle, then the flowdiagram 800, at step 860, automatically brakes the vehicle, for example,using an auto-braking system. In some embodiments, the auto-brakingfeature can be applied until the rail vehicle comes to a complete stop,or until the vehicle speed is below a determined threshold (e.g., below2 miles per hour or below the speed limit for that portion of thetrack), depending on the conditions and the situation. In someembodiments, once the vehicle has been brought to a stop or otherwisehas been brought into compliance with the control signal, any warningsignals currently generated (e.g., by step 840) may cease or be alteredto notify the vehicle operator of the current state of events.

In the event that the VMCS automatically stops the vehicle, the brakecan be continually applied until the operator acknowledges that he orshe is prepared to again assume control of the vehicle. Thisacknowledgement can be accomplished by pressing a confirmation button onthe user interface. When pressed, the brake can be released and systemoperation is returned to normal. Note that the braking event and theacknowledgement events and times can be logged.

The VMCS may provide a way for status messaging to be uploaded to therail network. Access points may be located periodically along the track(for example, vehicle storage yards or turn-around points). At thesepoints, information may be transferred to and from the vehicle and railnetwork.

The systems and methods disclosed herein can provide additional layer(s)of protection for transit operations by warning the vehicle operatorwhen operating rules are violated. If necessary to restore safeoperating margins, the VMCS can cause the vehicle slow or stop using thevehicle's full service brake. The protection provided by these systemsand methods can include signal compliance, speed limit compliance,vehicle-to-vehicle collision avoidance, operations and incidentrecording, work-zone temporary speed limits, vehicle location tracking,and precision station stopping. The techniques described herein canfunction by independently monitoring operating conditions such asvehicle speed, signal indications, and local speed restrictions on thetransit line.

The techniques can operate through the use of multiple sensing andcommunication technologies which are mounted on the vehicle and atstrategic wayside locations. The vehicle-side portion of the system canoperate autonomously and make internal operational decisions withoutrequiring a central server. The techniques can adapt to a transitsystem's existing operating rules and may not require the addition ofrestrictive block controls or additional vehicle spacing, avoidingadverse impact on existing system throughput. The techniques can operateas an overlay to the existing safety controls in transit systems byinterfacing in a non-invasive means with legacy vital signals. Thissystem enhances safety by providing warnings and/or actions which mayinclude automatic braking in the event the transit vehicle operatorfails to comply with operating rules and procedures. The techniques maycomply with IEC61508 SIL 3.

The techniques may be used as a safety enhancement to supplementexisting procedures and safe operating principles that transit vehicleoperators are trained to follow. In order to avoid compromising theexisting “safety net” already achieved with established operatingbehaviors, the techniques disclosed herein may to diminish or suppressoperator responsibility. For example, instead of notifying the operatorwhen the vehicle is approaching a track signal which is displaying a red(stop) indication, the techniques may not indicate a warning simplybecause the vehicle is approaching a red signal. Instead, the techniquesmay wait until the VMCS calculates that the approach speed to the redsignal is beyond what has been determined as a reasonably safe operatingmargin. Only when vehicle operation has exceeded the established safeoperating parameters will the techniques indicate a warning. If the safeoperating margin continues to deteriorate because the operator fails toimmediately slow the vehicle to a stop, the techniques can escalateintervention by automatically causing application of vehicle brakesuntil the vehicle comes to a stop.

This approach may keep the vehicle operator accustomed to being theprimary facilitator of safe operation. In an alternative implementation,the techniques were to warn the operator every time the vehicle wasapproaching a condition that requires slowing or stopping, the operatormay eventually become complacent. In time, under this alternativescenario, the operator may come to depend upon the system to maintainsafe operation instead of being vigilant and observant. This alternativeapproach may compromise the intended safety enhancement intended.

According to one technique, in order to assure that the operator retainsoperational responsibility, the methods and systems keep a log of theconditions for each event where it intervenes by indicating a warning orby applying vehicle brakes. This log can include the nature of theintervention, the justification for the intervention, the date, time,vehicle ID, vehicle speed, vehicle direction of travel, operating track,location, and, where applicable, the distance to the signal, othervehicle, or the speed limit for the track segment. Audits of logs mayhighlight if a particular operator is in need of additional training ordiscipline.

According to a technique, the system may operate using a peer-to-peerdata communications network (e.g., an ad-hoc network) between vehiclesand signals. As components come into communications range, they enterthe network. Such a decentralized approach may allow each vehicle todetermine its safe operating envelope using only the necessary localinputs from signals and other vehicles.

FIG. 9 illustrates a vehicle management control system 1000 (orvehicle-mounted subsystem), and may be similar to VMCS 10. For example,either the VMCS 1000 or VMCS 10 may be adapted to perform the techniquesdisclosed herein. The VMCS 1000 may include a backup power module 1001,a power supply/charger 1002, a data radio 1003, one or more rangingradios 1004, a GPS radio 1005, an override switch 1006, a user interface1007, an RFID reader 1008, an RFID antenna 1009, a control electronicsmodule 1010, a speed sensor 1011, and/or a vehicle interface 1012. Thecontrol electronics module 1010 may include one or more processors (or,for simplicity, a processor) and one or more memories. The controlelectronics module 1010 may control the operations of peripheralcomponents and receive data from them as well.

The VMCS 1000 may include a power supply 1002 and/or charger and abackup power source 1001 (e.g., batteries) rechargeable by the charger1002. The power supply 1002 may provide suitable electrical power to theremainder of the VMCS 1000. The power supply 1002 may receive power fromthe vehicle.

The data radio 1003 may be a peer finder. The data radio 1003 may becapable of detecting other peers, such as another VMCS 1000, a signalcontrol subsystem, a temporary control subsystem, or an access point,all of which are discussed below. Once peers have been identified, apeer-to-peer network may be created. The peer-to-peer network mayoperate independently of a central network, such as the rail networkdiscussed above.

The control electronics module 1010 may determine or recognize thepresence of peers detected by the data radio 1003. The data radio 1003may also serve to transfer data to and from other peers. The datanetwork may be a spread-spectrum network and may employ frequencyhopping. Such techniques may improve signal quality and robustness ofthe network. The data network may share speed and location of thevehicle with the other peers. This may facilitate determining a properseparation distance between the peers (be they other VMCSs or signalcontrol subsystems). The data network may allow wireless data uploads ofdaily operation logs and fault reports, for example, with an accesspoint. Information may be transmitted to a central network, eitherthrough another peer or directly, that includes operating data of thevehicle (e.g., location and speed) or faults that have been detected.

Once another peer is added to the network, the control electronicsmodule 1010 may operate one or more ranging radios 1004 to communicatewith the other peers. The radios may be described as “ranging,” becausethey may operate in conjunction with the control electronics module 1010to determine a distance between the VMCS 1000 and a given peer. Distancemay be determined by time-of-flight of the communications with anotherpeer. For example, a signal may be sent to a peer and it may bereturned, and the time-of-flight may be calculated, thereby providinginformation about the distance to the peer.

One particularly useful technology for the ranging radios 1004 is an UWBnetwork. UWB may provide a wide bandwidth distance measurement signalthat can be used to measure distance, for example, within inches. UWBmay be resistant to multipath distortions. Narrow-band time-of-flightdistance measurement systems may suffer from multipath distortion. UWBmay be compatible with varying operating environments including oneswith buildings and walls (which cause reflections), curved tunnels, andunderground. In addition to determining range information, the UWBnetwork may be used to communicate data, such as: the VMCS's unique ID,a signal indication, a track number, a track direction, the vehiclespeed, the vehicle direction of travel, or GPS information (positioninformation and/or GPS clock value).

The GPS radio 1005 may be capable of receiving GPS information fromsatellites. This information may be translatable into a position by thecontrol electronics module 1010. The GPS operating frequency may be1.575 GHz (civilian frequency). The GPS information may include absolutelocation and time/date information. The location information may be usedto derive speed of the vehicle. The location and speed information maybe used for collision avoidance techniques as discussed herein. Theposition/speed information may also be communicated to other peers or toa central network. The speed data may be used to automaticallycompensate for wheel wear when determining speed via the speed sensor1011 discussed below. The time information may be used for datatimestamps as well as local real-time clock calibration to allowaccurate logging of event times.

The VMCS 1000 may include an override switch 1006 to override operationof the VMCS 1000. In the override state, the vehicle may return to itsnative functioning (i.e., the functioning of the vehicle prior toinstallation of the VMCS 1000). The override switch 1006 may be aphysical actuator or an electronic signal.

The user interface 1007 may include one or more displays, input devices,or speakers. The user interface may receive inputs through the inputdevice(s) from an operator. System information may be displayed on thedisplay(s). Alerts may also be displayed on the display(s). Thespeaker(s) may also produce alerting sounds.

The RFID reader 1008 may operate with its antenna 1009 (collectively,RFID subsystem) to scan RFID tags located outside of the vehicle (e.g.,trackside). The RFID network may operate in the 900 MHz ISM band. Thetags may be passive or active tags. When the RFID reader 1008 approachesa tag, the contents of the tag may be retrieved and processed by thecontrol electronics module 1010. The RFID tag may contain a unique ID.The control electronics module 1010 may use that unique ID to retrieveadditional information about the tag from a database (e.g., a databasestored in the memor(ies) of the control electronics module 1010. Suchinformation (which may also be directly stored on the RFID tag) mayinclude location, speed limit, track direction, distance to a controlsignal subsystem, or the like. If the speed of the vehicle is greaterthan the indicated speed limit, then feedback may be provided throughthe user interface 1007 (for example, alerting the operator visually orthrough sound that a speed limit has been exceeded).

The RFID subsystem may be employed to allow the VMCS 1000 to determinewhen the vehicle is a predetermined distance away from an upcomingsignal along the direction of travel. This may provide a calibrationcheck of the UWB and GPS subsystems. By locating a particular RFID tagon the track at a consistent distance before a track signal, or at adistance noted in the data stored in the RFID tag, the distancemeasurement accuracy may be periodically verified. In the event the RFIDinformation indicates that the vehicle is approaching a particularsignal but that signal is not being detected (for example, by radios1003 or 1004), it may be determined that there is a problem such as afault in the VMCS 1000 radios or a fault in the radios of the missingpeer. Such information may be logged or reported to the operator throughthe user interface or reported to another network such as a centralnetwork.

The speed sensor 1011 may sense the number and/or rate of revolutions ofone or more wheels on the vehicle. This component may be added onto anexisting vehicle (prior to installation of the VMCS 1000), or mayalready be installed on the existing vehicle. The speed sensor may be amagnetic or optical sensor that, for example, measures a given number ofpulses per wheel rotation. The speed sensor may also provide informationrelating to the direction of wheel rotation. The speed sensor may outputa digital or analog signal (e.g., voltage with the magnitude beingproportional to speed).

The VMCS 1000 may include a vehicle interface 1012 that interfaces withexisting vehicle controls and data. The vehicle interface 1012 mayinterface with the vehicle's existing brake system. The brake systeminterface may include a switch that interrupts the vehicle's brake loop.The vehicle may include a fail-safe feature that automatically engagesthe brake when the brake loop is interrupted. The VMCS 1000 can leveragethis vehicle feature by opening the brake loop when a braking event isdetermined by the control electronics module 1010.

The brake system interface may include a switch. An exemplary switch maybe, for example, a relay (solid state or mechanical). The first contactof the switch may connect to a first side of the brake loop and thesecond contact may be connected to a second side of the brake loop. Toinstall the switch, an installer may find a suitable conductor on thebrake loop, cut it, and then install the switch contact to each side ofthe cut conductor. It may also be possible to install the switch throughother techniques. For example, an existing connector (e.g., terminal)can be removed from a contact on the existing vehicle and then moved tothe connector the first contact on the switch. A jumper from the secondcontact of the switch may be run back to the original contact on theexisting vehicle.

The processor of the control electronics module 1010 may cause theswitch to open upon a braking event, thereby disconnecting the firstcontact from the second contact. This will cause the vehicle's brakingalgorithm and implementation to activate. The control electronics module1010 may cause an alert to be generated by the user interface 1007(visual and/or auditory) that there has been an automatic braking event(i.e., not a braking event caused by the operator's direct interactionwith a braking actuator).

The control electronics module 1010 may then close the switch afterexpiration of the braking event. Such expiration may occur after a givenperiod of time (e.g., one minute) and/or upon a change in status of anoperator-controlled input. For example, after a suitable period of time,the control electronics module 1010 may receive an input from the userinterface 1007 indicating that the braking event should end. This mayoccur through an operator acknowledging and ending the braking event byinteracting with the user interface 1007.

FIG. 10 illustrates a control signal interface subsystem 1100 thatinterfaces with a signal control 2100. FIG. 10 and its functions may besimilar to those discussed above in context of the signal control point40. The control signal interface subsystem 1100 may be added to anexisting signal control 2100. The signal control 2100 may include signalcontrols 2101 and signals 2102. The signal controls 2101 may causeillumination of appropriate signals 2102. The signal control subsystem1100 may interface with the signals through one or more signalconverters 1101. This information may be received by one or moreprocessors 1104. One or more of the signal converters 1101 may alsoprovide power to the processor 1104 (not shown). The signal converters1101 may also include isolation circuitry, for example, to reduce therisk of a ground fault through the control signal interface subsystem1100. The data radio 1102 may operate in a similar fashion to data radio1003 of the VMCS 1000 discussed above. The ranging radio(s) 1103 mayoperate in a similar fashion to ranging radio(s) 1104 of the VMCS 1000discussed above. The signal information may also be communicated topeers through the data radio 1102 and/or ranging radio(s) 1103.

The VMCS 1000 and control signal interface subsystem 1100 may operate inthe following manner. The VMCS 1000 is mounted on a vehicle travellingtowards a control signal to which a control signal interface subsystem1100 is mounted. The VMCS 1000 searches for peers through the data radio1003 (e.g., spread-spectrum frequency hopping data network). The controlelectronics module 1010 detects and identifies the control signalinterface subsystem 1100 as a peer and adds it to the VMCS 1000recognized peer list.

The VMCS 1000 then communicates with the control signal interfacesubsystem 1100 via the ranging radio(s) 1004 and 1103 (e.g., UWBnetwork). The VMCS 1000 receives control signal status information fromthe control signal interface subsystem 1100 (e.g., what signal light isbeing displayed) via the ranging radio(s) 1004, 1103 or the data radios1003, 1102. The VMCS 1000 determines the time-of-flight of one or morecommunications (e.g., single-segment or round-trip communications). Thecontrol electronics module 1010 of the VMCS 1000 then calculates thedistance between the VMCS 1000 and the control signal interfacesubsystem 1100 based on the time-of-flight. The distance may also becalculated (for example, redundantly) based on GPS data. The distancemay also be calculated based on RFID tag location data in addition tothe known speed of the vehicle. For example, given a known RFID taglocation, the distance of a vehicle can be determined by continuouslytracking the speed of the vehicle after passing the RFID tag location.

An alert may be generated via the user interface 1007 by the controlelectronics module 1010 if the distance between the VMCS 1000 and thecontrol signal interface subsystem 1100 is less than a threshold. Thisdistance threshold can vary (e.g., vary in real-time) according to anumber of factors, such as: speed of vehicle; rate of change of speed ofvehicle (acceleration or deceleration); track speed limit; trackconditions (e.g., icy or we tracks); temperature; track grade (e.g.,steepness); work zone status; and/or the like. The threshold is exceededwhen the VMCS 1000 determines that, given the relevant factors, thedistance is becoming too close with the control signal interfacesubsystem 1100. Exceeding this threshold, or a different threshold, maycause the VMCS 1000 to cause the vehicle braking system to initiate(e.g., by interrupting the vehicle brake loop). Thresholds for alertand/or an automatic braking event may be the same or different. Forexample, the VMCS 1000 may only cause an alert when the vehicleoperating conditions and position are getting near to a dangerouscondition. A braking event may be caused only when the conditions andposition actually become dangerous. A different type of alert may begenerated when an automatic braking event takes place. According to onetechnique, alerts can be initiated upon exceeding a first threshold andthe alert can continue escalating in severity over time if no correctiveaction is taking place. The alert can escalate until the situationbecomes sufficiently dangerous that the vehicle may not be capable ofsafely stopping before the control signal (or such lack of capability issufficiently imminent). The alert can then escalate further or changecharacter once an automatic braking even takes place.

The VMCS 1000 may employ alerts and/or automatic braking events topromote compliance with rules. A rule may have one or multiplecomponents. Such rules may be associated with control signal states.Different control signal states may include red, yellow, green, doublered, or double yellow. Each control signal state may have an associatedset of behaviors required for vehicles observing such a state. A redsignal may mean the following: stop the vehicle; remain stopped for aperiod of time (e.g., one minute); and proceed after stopping at arestricted speed (e.g., 10 miles per hour or less until the nextsignal). A yellow signal may mean proceed with caution and be preparedto stop at the next signal. A green signal may mean proceed at anauthorized speed. A double red (or red over red) may mean stop and stayonly until an authorized person hand flags the vehicle past the signal.A double yellow (or yellow over yellow) may mean stop and then proceedat a restricted speed with caution (because, for example, a stationahead is occupied by a train).

Besides color coded signals, other signals may report system problems.For example, an “imperfect display” signal may indicate if one or morelights on the control signal are malfunctioning. For example, a controlsignal generally has only one signal illuminated—no more, no less. If nosignal is illuminated, or if more than one signal is illuminatedsimultaneously, then there may be an imperfect display. Proper responseto such a signal may depend on which type of light is defective. An“imperfect display at an interlocking” may indicate that the vehiclemust stop and should not proceed unless authorized by an authorizedperson. An “imperfect display at an automatic block signal” may indicatethat the vehicle should stop, wait for a duration of time (e.g., oneminute), and then proceed at a restricted speed (e.g., not greater than10 miles per hour).

The VMCS 1000 may promote compliance with such signals by monitoring avehicle's behavior as compared to a rule. If one or more components of arule are violated, then the VMCS 1000 may cause an alert and/or brakingevent. For example, if a signal is red, then a rule may include thefollowing components: (1) come to a safe stop before reaching thesignal; (2) wait for one minute; and (3) proceed after stopping at aspeed of 10 miles per hour or less. The VMCS 1000 enforces compliancewith each one of these components. As discussed above, the VMCS 1000 canenforce compliance of the first component of coming to a safe stopbefore reaching the signal. Then, the VMCS 1000 can ensure that thevehicle remains stopped for one minute (other intervals can also bechosen). If the vehicle begins moving prior to the expiration of the oneminute timer, then the VMCS 1000 can cause an alert and/or automaticbraking event. After stopping for one minute, the VMCS 1000 can thencause an alert and/or automatic braking event if the vehicle does notcomply with the third component of the rule—proceeding at a reducedspeed of 10 miles per hour or less. Thus, the VMCS 1000 can monitor andenforce complex vehicle behavior for rules that require safe stopping,stopping duration, or reduced vehicle speed. Rules may also involvemaintaining safe separation distances from other vehicles. For example,a rule may adjust a safe separation distance.

The VMCS 1000 may also communicate with an access point (e.g., via thedata radio 1003 and/or ranging radio(s) 1004). Data logs includingvehicle incidents (e.g., alarm-generating incidents) and speed-limitcompliance may be stored in the control electronics module 1010. Thisinformation can be communicated with the access point and then forwardedto a centralized network (e.g., a rail network). The access point mayalso communicate data to the VMCS 1000. Such data may include, forexample, track conditions, weather, and/or an updated RFID tag database(which may include location, work zone status, speed limit, etc.). Inaddition to communicating this information wirelessly, it may becommunicated with an access point via a physical connector (for example,connected to an access port on the VMCS 1000).

In addition to communicating with a control signal interface subsystem1100, the VMCS 1000 may also communicate with another VMCS on anothervehicle. Such VMCS-to-VMCS communications may be implemented asdiscussed with respect to the VMCS-to-control signal interface subsystemcommunications. The VMCS-to-VMCS communications may be employed todetermine safe vehicle separation distances. Thresholds and automaticbraking events may be determined in similar fashion as those determinedin the context of the VMCS 1000 interacting with the control signalinterface subsystem 1100. To avoid collisions by maintaining adequatevehicle-to-vehicle separation, braking event thresholds may bedetermined by accounting for factors of the remote vehicle, such as theremote vehicle's speed, rate of change of speed, direction, or the like.As more peers are added to the network (be they other VMCS's or controlsignal interface subsystems), new safe operating thresholds can bedetermined for each new peer.

Other types of peers are also possible. For example, a peer may be atemporarily fixed unit. An example is a maintenance crew's portable unitor a temporary slow-down marker. These types of peers may be constructedand function in a fashion similar to that of the control signalinterface subsystem 1100 and may cause the VMCS 1000 to issue alertsand/or cause automatic braking events upon exceeding safe operatingthresholds in the manners discussed above.

Aspects of the techniques described herein may be implemented in digitalelectronic circuitry, computer software, firmware, or hardware,including the structures disclosed herein and their structuralequivalents, or in various combinations. Aspects of the techniquesdescribed herein may be implemented as one or more computer programs,for example, one or more sets of program instructions residing on orencoded in a computer-readable storage medium for execution by, or tocontrol the operation of, one or more processors. Alternatively or inaddition, the instructions may be encoded on an artificially-generatedpropagated signal, for example, a machine-generated electrical, optical,or electromagnetic signal that may be generated to encode informationfor transmission to a suitable receiver apparatus for execution by oneor more processors. A computer-readable medium may be, or be includedin, a computer-readable storage device, a computer-readable storagesubstrate, a random or serial access memory array or device, variouscombinations thereof. Moreover, while a computer-readable medium may ormay not be a propagated signal, a computer-readable medium may be asource or destination of program instructions encoded in anartificially-generated propagated signal. The computer-readable mediummay also be, or be included in, one or more separate physical componentsor media (for example, CDs, disks, or other storage devices).

Certain techniques described in this specification may be implemented asoperations performed by one or more processors on data stored on one ormore computer-readable mediums or received from other sources. The term“processor” may encompass various kinds of apparatuses, devices, ormachines for processing data, including by way of example a centralprocessing unit, a microprocessor, a microcontroller, a digital-signalprocessor, programmable processor, a computer, a system on a chip, orvarious combinations thereof. The processor may include special purposelogic circuitry, for example, a field programmable gate array or anapplication-specific integrated circuit.

Program instructions (for example, a program, software, softwareapplication, script, or code) may be written in various programminglanguages, including compiled or interpreted languages, declarative orprocedural languages, and may be deployed in various forms, for exampleas a stand-alone program or as a module, component, subroutine, object,or other unit suitable for use in a computing environment. Programinstructions may correspond to a file in a file system. Programinstructions may be stored in a portion of a file that holds otherprograms or data (for example, one or more scripts stored in a markuplanguage document), in a dedicated file or in multiple coordinated files(for example, files that store one or more modules, sub-programs, orportions of code). Program instructions may be deployed to be executedon one or more processors located at one site or distributed acrossmultiple sites connected by a network.

The present technology has now been described in such full, clear,concise and exact terms as to enable any person skilled in the art towhich it pertains, to practice the same. It is to be understood that theforegoing describes preferred embodiments and examples of the presenttechnology and that modifications may be made therein without departingfrom the spirit or scope of the invention as set forth in the claims.Moreover, it is also understood that the embodiments shown in thedrawings, if any, and as described above are merely for illustrativepurposes and not intended to limit the scope of the invention. As usedin this description, the singular forms “a,” “an,” and “the” includeplural reference such as “more than one” unless the context clearlydictates otherwise. Where the term “comprising” appears, it iscontemplated that the terms “consisting essentially of” or “consistingof” could be used in its place to describe certain embodiments of thepresent technology. Further, all references cited herein areincorporated in their entireties.

What is claimed:
 1. A system for evaluating vehicle operationcompliance, wherein the system comprises: a control signal interfacesubsystem; and a vehicle-mounted subsystem configured to: communicatewith the control signal interface subsystem to receive informationcorresponding to a status of a control signal; determine a rule forbehavior of a vehicle according to the information corresponding to thestatus of the control signal; and observe operation of the vehicle toevaluate compliance with the rule; wherein: the control signal interfacesubsystem comprises an ultra-wideband (UWB) communications component;the vehicle-mounted subsystem comprises an ultra-wideband (UWB)communications component; and the vehicle-mounted subsystem and thecontrol signal interface subsystem are further configured to communicateUWB signals carrying data pertinent to evaluating vehicle operationcompliance, the data comprising at least one of: a unique ID associatedwith the vehicle-mounted subsystem, a signal indication, a track number,a track direction, speed, and direction of travel.
 2. The system ofclaim 1, wherein the rule corresponds to the status of the controlsignal being at least one of red, double red, yellow, or double yellow.3. The system of claim 1, wherein the rule specifies a stop-timeduration for the vehicle.
 4. The system of claim 3, wherein the rulespecifies a speed for the vehicle.
 5. The system of claim 4, wherein therule specifies a maximum speed for the vehicle after an expiration ofthe stop-time.
 6. The system of claim 1, wherein the vehicle-mountedsubsystem is configured to: interface with a braking system of thevehicle; communicate with the UWB communications component of thecontrol signal interface subsystem via the UWB communications componentof the vehicle-mounted subsystem; and determine a distance between thevehicle-mounted subsystem and the control signal interface subsystembased on a time-of-flight of at least one communication between the UWBcommunications component of the control signal interface subsystem andthe UWB communications component of the vehicle-mounted subsystem. 7.The system of claim 1, wherein the vehicle-mounted subsystem is furtherconfigured to generate an alert if a distance between thevehicle-mounted subsystem and the control signal interface subsystem isless than a threshold.
 8. The system of claim 1, wherein thevehicle-mounted subsystem is further configured to cause a brakingsystem of the vehicle to activate if a distance between thevehicle-mounted subsystem and the control signal interface subsystem isless than a threshold.
 9. The system of claim 1, wherein thevehicle-mounted subsystem further comprises a radio-frequencyidentification (RFID) subsystem configured to scan at least one RFID tagexternal to the vehicle to retrieve information stored on the at leastone RFID tag.
 10. The system of claim 9, wherein: the vehicle-mountedsubsystem is further configured to substantially continuously receiveinformation relating to speed of the vehicle; and the vehicle-mountedsubsystem determines a changing distance between the vehicle-mountedsubsystem and the control signal interface subsystem based on theinformation stored on the at least one RFID tag and the informationrelating to speed of the vehicle.
 11. The system of claim 9, wherein thevehicle-mounted subsystem is further configured to determine a distancebetween the vehicle-mounted subsystem and the control signal interfacesubsystem based on the information stored on the at least one RFID tag.12. The system of claim 1, further comprising: an access point externalto the vehicle; and wherein the vehicle-mounted subsystem is furtherconfigured to: store data relating to prior behavior of the vehicle; andcommunicate the data relating to prior behavior of the vehicle with theaccess point.
 13. The system of claim 1, further comprising: a secondvehicle-mounted subsystem including a UWB communications component,wherein the second vehicle-mounted subsystem is configured to be mountedon another vehicle; and wherein the vehicle-mounted subsystem isconfigured to: communicate with the UWB communications component of thecontrol signal interface subsystem via the UWB communications componentof the vehicle-mounted subsystem; communicate with the UWBcommunications component of the second vehicle-mounted subsystem via theUWB communications component of the vehicle-mounted subsystem; determinea distance between the vehicle-mounted subsystem and the control signalinterface subsystem based on a time-of-flight of at least onecommunication between the UWB communications component of the controlsignal interface subsystem and the UWB communications component of thevehicle-mounted subsystem; and determine a distance between thevehicle-mounted subsystem and the second vehicle-mounted subsystem basedon a time-of-flight of at least one communication between the UWBcommunications component of the second vehicle-mounted subsystem and theUWB communications component of the vehicle-mounted subsystem.
 14. Thesystem of claim 13, wherein the vehicle-mounted subsystem is furtherconfigured to: generate an alert if the distance between thevehicle-mounted subsystem and the control signal interface subsystem isless than a first threshold; and generate an alert if the distancebetween the vehicle-mounted subsystem and the second vehicle-mountedsubsystem is less than a second threshold.
 15. The system of claim 13,wherein the vehicle-mounted subsystem is further configured to: cause abraking system of the vehicle to activate if the distance between thevehicle-mounted subsystem and the control signal interface subsystem isless than a first threshold; and cause the braking system of the vehicleto activate if the distance between the vehicle-mounted subsystem andthe second vehicle-mounted subsystem is less than a second threshold.16. The system of claim 13, wherein the vehicle-mounted subsystemfurther comprises: a radio-frequency identification (RFID) subsystemconfigured to scan at least one RFID tag external to the vehicle toretrieve information stored on the at least one RFID tag; and whereinthe vehicle-mounted subsystem is further configured to determine adistance between the vehicle-mounted subsystem and the control signalinterface subsystem based on the information stored on the at least oneRFID tag.
 17. The system of claim 16, wherein: the vehicle-mountedsubsystem is further configured to substantially continuously receiveinformation relating to speed of the vehicle; and the vehicle-mountedsubsystem determines a changing distance between the vehicle-mountedsubsystem and the control signal interface subsystem based on theinformation stored on the at least one RFID tag and the informationrelating to speed of the vehicle.
 18. The system of claim 13, furthercomprising: an access point external to the vehicle; and wherein thevehicle-mounted subsystem is further configured to: store data relatingto prior behavior of the vehicle; and communicate the data relating toprior behavior of the vehicle with the access point.